Synthesis, characterization of poly(m-phenylenediamine)/palygorskite and its unusual and reactive adsorbability to chromium(VI)

A nanocomposite of poly(m-phenylenediamine)/palygorskite (PmPD-PG) is facilely synthesized via in situ oxidative polymerization of m-phenylenediamine (mPD) on palygorskite (PG) and its reactive adsorbability to Cr(VI) is examined. PG in the nanocomposite plays important roles in the improvement of adsorptivity of Cr(VI). The pH value of the solution is increased after adsorption, which is quite different from Pb(II) adsorption with aromatic diamine polymers. This unusual removal behavior of Cr(VI) with PmPD-PG is due to the redox reaction between Cr(VI) and amino/imino groups on the PmPD chains.